Darbo tikslas – nustatyti aminorūgščių, esančių skystųjų amidinio azoto trąšų sudėtyje, panaudotų papildomam žieminių kviečių tręšimui per lapus poveikį augalų biologiniam potencialui. Ginamieji disertacijos teiginiai: 1. Aminorūgščių trąšos skatina žieminių kviečių lapų fotosintezės aktyvumą bei didina fotosintetinių rodiklių parametrus. 2. Skirtingų aminorūgščių koncentracijų tirpalai, naudojami įvairiais augalų vystymosi tarpsniais, nevienodai įtakoja žieminių kviečių grūdų derlingumą. 3. Aminorūgštys, naudojamos tręšimui per lapus, teigiamai veikia žieminių kviečių grūdų kokybę bei baltymų ir aminorūgščių kiekybinę ir kokybinę sudėtį. / Aim of the work The study was designed to establish the effects of amino acids, present in the composition of liquid amide nitrogen fertilizers, applied as additional foliar feeding on winter wheat. Proposition to be defended: 1. Amino acid fertilization promotes winter wheat leaf photosynthetic activity and increases parameters of photosynthetic indicators. 2. Different concentrations of amino acids applied at various plant growth stages highlight the differences of their efficacy for winter wheat grain yield. 3. Foliar–applied amino acids positively affect winter wheat grain quality and quantitative and qualitative composition of proteins and amino acids.

The transfer of N from legume green manures (GMr) can satisfy the needs of a successive cash crop, but rotations that have over-wintering legumes also carry an increased risk of off-season (Sep.–June) N losses, especially during spring thaw. Spring-wheat yield among four GMr systems were evaluated with respect to off-season (GMr; Sep.–June) and in-season (wheat; June–Sep.) N2O emissions, as well as full-year NO3– leaching and dissolved N2O losses during spring-thaw from a tile-drained sandy loam soil in Atlantic Canada over 2 rotations (2011–2013). Four GMr systems (treatments) differed in the timing and season of GMr incorporation and the use of additional N as fertilizer or manure. The majority (66%) of cumulative N2O emissions were measured during the off-season because of high N2O emissions events during spring thaw. There was no clear effect of GMr system on these emissions, which may have been a result of the pattern and duration of soil freezing and thawing. Spring thaw also coincided with the highest dissolved N2O concentrations (100–300 µg N2O-N L–1) in tile-drained water, which represented potential N2O emissions of 21 to 116 g N2O-N ha–1. Belowground N2O concentrations and soil water content measurements during winter provided further evidence of the relationship of N2O dissolved in drainage water and N2O emissions at the soil surface. Wheat yield among treatments in either year of study were not different, but was 1.5 times greater in Year 2 (2.62 ± 0.27 Mg ha–1), than Year 1 (1.05 ± 0.12 Mg ha–1). The highest NO3– concentrations in drainage water (Oct.; 13.8 mg NO3–-N L–1) were measured from the GMr system with the earliest fall incorporation (i.e., Sep.) and the addition of spring fertilizer when compared to the mean of all other treatments (9.8 mg NO3–-N L–1). The use of supplemental N did not translate into additional gains in yield, yet increased in-season N2O emissions and greater NO3– leaching. Off-season N losses proved to be a substantial part of the annual N loss budget and dissolved N2O in drainage water was identified as an additional pathway for N loss at spring thaw.

Since ancient times, roads have tied people and cultures together. Roads have been createdwith the aim of facilitating trade and cultural exchange among different regions in the world. After the technologic development in vehicle industry and dramatically increase of motoring in the world during the past century road communication has gained a great importance for transporting people and goods. Thus, good safety and accessibility on roads all year round is now a vital necessity for a healthy economy in all modern societies. In order to keep roads safe, available for use with high transport quality they need to be maintained in real time. One of the most difficult tasks in this context is to keep the roads in good condition and accessible even during winter. The main objective of this doctoral thesis is to attempt to specify the most efficient ways of executing winter road maintenance.  The preliminary issue in this context is whether it is the use of current assistive tools, that is, technical aspects that should be optimized and developed or whether it is the way in which winter maintenance services are procured and outsourced, that is, contractual aspects that should be improved which could give the optimal impact for both clients and contractors and make winter road maintenance more effective, or both issues. In order to define the outline of the research project a comprehensive state of the art survey was initiated with the intention of collecting and gaining insights into the earlier studies in the research area. Three basic areas associated with the performance of winter road maintenance were considered to be most relevant for review due to the anchorage between the areas. The selected areas were climatological, technical and contractual aspects. The literature review was followed by an electronic questionnaire survey. The results of the study in this stage showed that current technical methods almost functioned in a reasonable manner but there was an imprecise dissatisfaction with the current maintenance contract. The second stage of the research consisted of a number of additional empirical investigations in order to identify contractual problematic issues behind the current winter road maintenance in Sweden. Generally, those factors that are rarely considered as potential underlying causes to costly performance of winter road maintenance in Sweden were studied in this research project for example improper use of related technical assistive tools, procurement of improper bundled winter services and inappropriate contract structure. This thesis consists of six papers, five of which are related to each other, and the first one is completely independent but within research area. Findings in the thesis contributes to extend understanding about; how designing appropriate contracts can improve winter road maintenance, how proper use of assistive tools can reduce unnecessary winter road maintenance costs and minimize road traffic disruptions and delays, how a partnering structure in contracts can create confidence and trust between clients and contractors that in turn leads to minimizing or eliminating conflicts and disputes between parties involved, how choice of appropriate procurement methods through proper bundling of winter road services can contribute to shorten the procurement process and create incentives for contractors, and how selection of proper payment mechanisms can contribute to higher service quality of performed winter road measures. Additionally, an adequate knowledge and understanding of climate, proper knowledge of road weather and its impact on winter road traffic is essential for contribution of better planning of how to maintain the road network during winter. Since understanding about winter issues and its effect on winter road traffic is far from complete and winter road maintenance in the cold regions is a similar challenge, broad and complex, the results of this research may even contribute to improving winter maintenance problems in the countries with severe winters like Sweden. / <p>QC 20140227</p>

In countries with severe winters such like Canada, winter road maintenance (WRM) operations, such as plowing, salting and sanding, play an indispensible role in maintaining good road surface conditions and keeping roads safe. WRM is, however, also costly, both monetarily and environmentally. The substantial direct and indirect costs associated with WRM have stimulated significant interest in quantifying the safety and mobility benefits of winter road maintenance, such that systematic cost-benefit assessment can be performed. A number of studies have been initiated in the past decade to identify the links between winter road safety and factors related to weather, road, and maintenance operations. However, most of these studies have focused on the effects of adverse weather on road safety. Limited efforts have been devoted to the problem of quantifying the safety benefits of winter road maintenance under specific road weather conditions. Moreover, the joint effects of and complex interactions between road driving conditions, traffic and maintenance and their impact on traffic safety have rarely been studied. This research aims to determine the effect of WRM on road safety during snow storm events and develop models that can be used to quantify the safety benefit of alternative winter road maintenance policies, strategies and practices. Two integral aspects of collision risk were investigated, namely, collision frequency and severity. Collision frequency models were developed using winter storm collision data compiled for six winter seasons (2000 to 2006) for a total of 31 highway routes across Ontario. A comprehensive measure, namely, road surface condition index (RSI), was proposed to represent the road surface conditions during a variety of snow events. RSI was used as a surrogate measure to capture the effects of WRM. Other factors related to weather, traffic and road features were also accounted for in the analysis. Problems associated with data aggregation were also investigated. For this purpose, two different datasets were formed, namely, event-based data (EBD) which aggregates data by snow storm events and hourly based data (HBD) which includes hourly records of collision counts and other related factors. These two data sets of different aggregation levels were then used to investigate the effects of data aggregation and correlation (within – event) as well as to develop models for different purposes of benefit analyses. For EBD, Negative Binomial models and Generalized Negative Binomial models were calibrated whereas for HBD, Generalized Negative Binomial models and multilevel Poisson Lognormal models were calibrated. Generalized Negative Binomial models were found to best fit the data for both datasets. It was found that addition of site specific variables improves model fit. RSI and exposure were found significant for all the models and datasets. Weather factors such as visibility, wind speed, precipitation, and air temperature were also found to have statistically significant effects on collision frequency. All the models were consistent in terms of effects of different variables. The EBD models are useful to quantify the effect of different maintenance service standards and policies with limited information on the details of the weather events and traffic. On the other hand, HBD models have a higher level of reliability capable of providing more accurate estimates on road accidents. As a result, they are useful for determining the effects of different treatment operations. Several examples were employed to demonstrate the application of the developed models, such as quantifying the benefits of alternative maintenance operations and evaluating the effects of different service standards using safety as a performance measure. To enable a comprehensive risk analysis, collisions under both all-weather conditions and snow storm conditions over the six winter seasons were analyzed to identify the relationship between collision severity and various factors related to road weather and surface conditions, road characteristics, traffic, and vehicles etc., on collision severity. A multilevel modeling framework was introduced to capture the inherent hierarchy between collisions, vehicles and persons involved within the collision data. For each collision data set, three alternative severity models, namely, multinomial models, ordered logit models and binary logit models, were calibrated and compared. It was found that multilevel multinomial logit models were best fit to the data. Moreover issues related to different levels of aggregation were also discussed and results from occupant based data were found to be more reasonable and in line with general literature. Different individual, vehicle, environment and accident location factors were found to have a statistically significant effect on the injury severity levels. Contributing factors at the individual and vehicle levels include driver condition, driver sex, driver age, position in vehicle, use of safety device such as seat belt, vehicle type, vehicle age and vehicle condition. Roadway and environment factors include number of lanes, speed limit, road alignment, RSI/road surface condition, wind speed, and visibility. Other factors include light, and traffic volume. Two case studies were conducted to demonstrate the application of the developed models in conjunction with the accident frequency models for cost benefit analysis. This research was the first to investigate the direct link between road surface conditions and collisions at an operational level. It has been shown that the developed models are capable of evaluating alternative winter road maintenance policies and operations and assessing the safety benefit of a particular winter road maintenance strategy or decision. This research is also the first to conduct an in-depth analysis on the problem of winter road safety at a disaggregate level that captures detailed temporal variation (e.g., hourly and by storm event)) within small spatial aggregation units (road sections corresponding to actual patrol routes). The safety models developed from this research could be easily incorporated into a decision support tool for conducting what-if analysis of alternative winter road maintenance policies and methods. Moreover these models could provide a mechanism to estimate road safety level based on road surface as well as weather and traffic conditions and therefore could potentially be used for generating safety related information for travelers as part of a winter traffic management scheme. Directions for future work are also provided at the end of this document.

Climate change is considered one of the primary threats to the sustainability of ski tourism around the world. Studies in several countries project the ski industry will be impacted by shorter ski seasons, greater snowmaking requirements, and a declining ski demand. Many supply-side studies suffer key limitations, such as the omission of snowmaking, leaving their conclusions highly questionable. This study utilizes the SkiSim 2 model to reassess the implications of projected climate change for two major ski tourism destinations in the Western USA (Vail, Colorado and Lake Tahoe, California) where previous studies projected major impacts when snowmaking was not considered. Historical climate data (1961-1990) and the stochastic weather generator LARS-WG are used to examine the impact of climate change scenarios for ski season length and snowmaking requirements by the 2050s. Comparisons with previous studies and implications for ski tourism development and planning will be discussed.

Degradation of water quality, introduction of dreissenid mussels (notably <i>Dreissena polymorpha</i>) and depletion of oxygen concentrations in the hypolimnion in Lake Simcoe, Ontario prompted a study of phytoplankton primary production to inform efforts to improve the lake conditions. The characterization of algal production is critical since, as primary producers, their biomass is positively correlated with production at higher trophic levels in pelagic food webs and oxygen levels. This study was conducted from August 2010 to August 2011, including the winter season (Dec-Mar). Temporally, the lake displayed a unimodal pattern with late summer to fall production maxima. For all seasons considered, the pelagic daily areal primary production (P_int) was lower in the nearshore than offshore, consistent with the nearshore shunt hypothesis that mussels should be able to deplete phytoplankton more effectively in the nearshore. The sensitivity analysis revealed that chl a and the photosynthetic parameter P^B_max were the most influential variables for explaining such spatial differences. The size distribution of chl a and production varied where both netplankton (>20µm) and nanoplankton (2-20µm) were greatest in fall and picoplankton (<2µm) was highest in summer and early fall. A large chl a peak of nanoplankton was also found in late-winter (Mar) at offshore stations. The seasonal areal primary production (SAPP; May-Oct) and chl a:TP were significantly lower nearshore than offshore, consistent with grazing impacts from the large nearshore dreissenid mussel community. The lake as a whole is quite productive comparable to other large lakes with comparable total P concentrations and dreissenid mussel populations. The latter part of the study showed that the deep chlorophyll layer (DCL) was not as frequent as expected and was detected only 28% of time during late-spring to summer when the lake was thermally stratified (Aug-Sept 2010 and May-Aug 2011). The percent dissolved oxygen (%) did not show any indications of elevated primary production in the DCL although the production estimates suggested that there is a substantial (an average of 55%) amount of primary production occurring below thermocline when a DCL exists. Whether or not the DCL has potential to nourish the benthic filterers (dreissenids) and has ecological significance in the lake remains unclear. Overall, the factors that control phytoplankton primary production in Lake Simcoe seem to operate somewhat differently from other large lakes and further investigation is needed to elucidate them. The analysis of primary production and biomass has improved knowledge of non-summer production and can provide guidance to site-specific P and oxygen remediation.

Thesis (Th. M.)--Covenant Theological Seminary, 2007. / Abstract. Includes bibliographical references (leaves 125-128).

Dissertation (MBus) -- AUT University, 2007. / Includes bibliographical references. Also held in print (x, 114 leaves : ill. ; 30 cm.) in City Campus Theses Collection (T 338.47796 LI)

Thesis (D.W.S.)--Robert E. Webber Institute for Worship Studies, 2008. / Abstract. Includes bibliographical references (leaves 99-105).

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 84-87). Also available on the Internet.